Fuel supply means for carburetors



Aug. 25, 1942. L, D. BQYCE' 2,293,884

FUEL SUPPLY MEANS FOR CARBURETORS- Filed March 28. 1941 27 I A *v 33 \l/ F I G 2 INVENTOR LEONARD DBOYCE V i ATTORNEY Patented Aug. 25, 1942 UNITED STATES PATENT OFFICE 2,293,884 FUEL SUPPLY MEANS FOR CABBURETORS Leonard D. Boyce, Maplewood, Mo., assignorto Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application March 28, 1941, Serial No. 385,638

8 Claims. moi. 123-139) This invention relates to carburetors for internal combustion engines and more particularly concerns carburetor float chambers and liquid fuel supply means.

Carburetor fuel chambers being usually closely associated with the engine receive considerable heat therefrom by conduction and radiation. This is particularly true in downdraft installations where the carburetor and float chamber are located immediately above the exhaust manifold. As a consequence, fuel retained for any appreciable period, as it is in conventional constructions, in these chambers boils and the more volatile fractions escape leaving the heavier portions which are not, readily atomized. -Upon subsequent operation therefore heavy fuel unsuitable for operation and particularly unsuitable for cold starting mixtures is delivered to the carburetor mixture conduit.

Another difficulty arising from the retention of fuel in the fuel chamber during inoperation is that percolation occasioned by fuel vaporizing in the heated carburetor fuel -passages may transfer substantially the entire quantity of fuel from the fuel chamber to the mixture conduit. This may and quite frequently does occur following hard driving during hot weather. Permitting this quantity of fuel to flow into the intake manifoldwould, obviously, give rise to great difliculty.

in subsequent starting of the engine.

Also in multiple carburetor installations in which one or part of the carburetor only are operative during the lower and normal range of speed and power operation, it will be seen that the fuel'in the float chambers of those carburetors which operate only through the high ranges of speed and power may be retained therein for indefinite periods, which may result in the higher range carburetors receiving stale or heavy fuel immediately upon coming into operation;

,It is an object of the present invention to overcome the above mentioned difliculties by the provision of a novel carburetor fuel chamber. It is a further object of the present invention to pro-. vide novel means for maintaining the constant predetermined level of fuel in the carburetor fuel chamber during operation of the engine and to substantially drain the chamber when the engine is inoperative.

Other objects and advantages will appear upo reference to the following description and accompanying drawing. Referring to the drawing Fig. 1 is a schematic view showing a fragmentary portion of an internal combustion engine, and installation of carburetor thereon embodying the present invention, a fragmentary portion of a fuel tank and a fuel transfer device.

Fig. 2 is an enlarged sectional view of a float The illustrated embodiments of the present invention involve a multiple carburetor installation having a manually controlled primary or (low speed and power range) carburetor equipped with a float chamber of conventional design and a secondary or (high speed and power range) carburetor. automatically controlled and equipped with a float chamber constructed in accordance with Fig. 2. It will 'be understood, however, that the adaptation of the present invention is equally advantageous in a single carburetor installation.

Numeral I generally indicates a portion of an internal combustion engine having an intake manifold 2 and an exhaust manifold 3 and having intake manifold heating jackets 4 and 5. Mounted on the intake manifold are the primary carburetor generally indicated at E and a secondary carburetor generally indicated at l. A fuel supply tank is indicated at 8 and an electrically driven centrifugal fuel pump 9 delivers fuel under pressure to the float chamber Ill of carburetor 6 and H of carburetor I. The design of pump 9 forms no part of the present invention other than, as previously stated, it is a centrifugal type pump and therefore valveless. Nor is it essential that the pump be electrically driven, it being necessary only that provision be made for rendering the pump inoperative when the engine ceases to operate.

In. the preferred arrangement, the pump is driven electrically, energy being supplied by a 1 storage battery B. The centrifugal pump 9 and chamber constructed in accordance with the.

engine ignition device generally indicated at C are commonly connected to the battery by a conductor l2 in which is interposed the usualignition switch l3. With this arrangement the engine and pump are jointly rendered inoperative. The fuel tank 8, as indicated, is situated below the level of the carburetor float chamber; as it usually is in motor vehicles.

Carburetor 5 is equipped with a mixture control valve it which is manually operated from a convenient pointby means of lever I5 and operating rod 16. Carburetor I is equipped with a mixture control valve l8. Valve I8 is connected to a bellows ill by means of lever 20 and link 2|. The bellows I9 is connected by the suction tube 22 to the mixture conduit of carburetor 6 at a point anterior to the valve I4. Valve I8 is urged toward a closed position by a spring 23 and is moved toward an open position against spring 23 by the collapsing of bellows l9 when the pressure drop in the conduit of carburetor 6 reaches a predetermined point. Fuel is supplied to the float chambers l0 and II by pump 9 through conduits 24, 25 and 26 and a substantially constant level, as indicated at A, is maintained therein during operation of pump 9 by the action of float 25 upon the intake needle valve 26. This operation is well known and understood.

passages 21 which communicates with the lower I part of the fuel chamber at 28 (see Fig. 2). Fuel chamber I I is provided with inlet passages 29 and 30 and a branch return passage 3| communicating therewith. Return passage 3| is controlled by a ball check valve 32 arranged to seat at 33. A valve retainer 34 is provided. As illustrated, passage 3! communicates with the float chamber at a level which will permit draining of the fuel chamber to a level 'below the outlet of passage 21. The inlet passageway 29, as shown, is formed concentric with return passage 3| which results in the incoming fuel impacting directly on valve 32 thereby causing the valve to be In operation, upon starting the engine, switc I3 is closed, the ignition devices and pump 8 being energized, the engine may be started by cranking. During the operation of cranking, pump 9 will have supplied fuel to the carburetor fuel chamber /"valve 32 being forced closed by the pressure of the incoming fuel. When the engine. -is""rendered inoperative by breaking the quicklyseated.

ignition circuit at switch l3, the pump will also.

be rendered inoperative and the fuel in chamber II will drain back through passage ll, 29 and conduits 26 and 24 and the centrifugal pump 9 to the fuel tank 8. Valve 33 being unseated by the head of fuel in the fuel chamber.

The following description and accompanying drawing are intended to be illustrative and not limiting and the exclusive use of all modifications within the scope of the appended claims is contemplated.

I claim:

1. In an internal combustion engine, a carburetor having a fuel chamber, a fuel supply tank located at a level below said fuel chamber, a centrifugal pump located in said supply tank for transferring fuel to said fuel chamber, a. conduit leading from the discharge side of said pump to said fuel chamber, a passageway in the wall of said fuel chamber communicating with said conduit and the interior of said fuel chamber, a float actuated valve controlling said passage, a second passageway in the wall of said fuel chamber communicating with said conduit and with the interior of said chamber at a point near the bottom thereof, and a check valve in said last-mentioned passageway arranged to be held closed by fuel pressure during the operation of said pump and to permit the return of fuel from said fuel chamber to said supply tank when said pump is inoperative.

2. In combination, an internal combustion engine, a primary and a secondary carburetor for said engine, said secondary carburetor being arranged to operate above a predetermined speed and/or load only, a constant level fuelchamber for each of said carburetors, a fuel supply tank located at a level below said fuel chambers, pump means for transferring fuel'from said supply tank to said fuel chambers, a passageway for returning fuel from said secondary carburetor fuel chamber to said supply tank; and a check valve and communicating with said fuel chamber near the bottom thereof, and a check valve in said branch operating to prevent fuel from entering said fuel chamber through said branch and permitting the flow of fuel therefrom.

4, In a carburetor, a fuel chamber, an inlet passageway to said fuel chamber, a float controlled valve iirsaid inlet passageway arranged to maintain a predetermined level of fuel in said chamber, a branch passageway diverging from said inlet passageway at a point anterior to said valve and communicating with said fuel chamber at a point below the predetermined fuel level, and a check valve in said branch passageway operating to prevent fuel from entering said chamber therethrough and permitting the flow of fuel therethrough from said chamber by av ty.

5. In combination with an internal combustion engine, a carburetor having a fuel chamber, a fuel supply tank normally located at a level below said fuel chamber, a centrifugal .pump for transferring fuel from said supply tank to said fuel chamber, a branched discharge passage connected to the discharge side of said pump and opening-as inlets at spaced points in said fuel reservoir, 9. float actuated valve for controlling one of said inlets, and a check valve for controlling the other of said inlets, said check valve being constructed and arranged to be held in a closed position by the pressure developed by said fuel pump.

6. In combination, an internal combustion engine, a carburetor having a fuel chamber, a fuel tank located at the level below said fuel chamber, means including a pump for transferring fuel from said supply tank to said fuel chamber, a passageway leading from said fuel chamber for returning fuel by gravity to said supply tank when said pump is inoperative, and a check valve in said passageway arranged to be held in a closed positionby the pressure of fuel being transferred by said pump.

7. In combination with an internal combustion engine, a carburetor having a fuel chamher, a fuel supply tank located at a level below said fuel chamber, a centrifugal pump for transferring fuel from said supply'tank to said fuel chamber, branched conductor means connected to the discharge side of said pump and at spaced points with the interior of said fuel chamber, a float actuated valve for controlling one of said branches, and a valve in the other of said branches arranged to be closed. by the pressure developed by said fuel pump and to be opened by the head of fuel in said fuel reservoir when said pump is inoperative to permit the return of fuel to said supply tank by gravity.

8. In combination with an internal combustion engine carburetor having a constant level fuel chamber, a float actuated valve for controlling the inlet to said chamber, an outlet from said fuel chamber, a check valve in said outlet arranged to permit the flow of fuel from said chamberand to prevent the flow thereinto, a fuel supply tank located at a level below said fuel chamber, a valveless pump for transferring fuel from said supply tank to said fuel chamber and a conduit jointly connecting said fuel chamber inlet and outlet with the discharge side of said pump whereby fuel is permitted to return from said fuel chamber to said supply tank during inoperation of said pump.

LEONARD D. BOYCE. 

